dplR (version 1.6.8)

chron: Build Mean Value Chronology

Description

This function builds a mean value chronology, typically from a data.frame of detrended ring widths as produced by detrend.

Usage

chron(x, prefix = "xxx", biweight = TRUE, prewhiten = FALSE, …)

Arguments

x

a data.frame of ring widths with rownames(x) containing years and colnames(x) containing each series ID such as produced by read.rwl

prefix

a character string with less than 4 characters. Defaults to "xxx"

biweight

logical flag. If TRUE then a robust mean is calculated using tbrm.

prewhiten

logical flag. If TRUE each series is whitened using ar prior to averaging.

…

Arguments passed to ar when prewhiten is TRUE. For example, use aic and order.max to control the order of the AR model.

Value

A data.frame with the standard chronology, residual chronology (if prewhitening was performed), and the sample depth.

Details

This either averages the rows of the data.frame using a mean or a robust mean (the so-called standard chronology) or can do so from the residuals of an AR process (the residual chronology).

References

Cook, E. R. and Kairiukstis, L. A., editors (1990) Methods of Dendrochronology: Applications in the Environmental Sciences. Springer. ISBN-13: 978-0-7923-0586-6.

Fritts, H. C. (2001) Tree Rings and Climate. Blackburn. ISBN-13: 978-1-930665-39-2.

See Also

read.rwl, detrend, ar, crn.plot

Examples

# NOT RUN {
library(graphics)
library(utils)
data(ca533)
ca533.rwi <- detrend(rwl = ca533, method = "ModNegExp")
ca533.crn <- chron(ca533.rwi, prefix = "CAM")
plot(ca533.crn,xlab="Year",ylab="RWI")
## With residual chron
ca533.crn <- chron(ca533.rwi, prefix = "CAM", prewhiten = TRUE)
# }